It has been almost 6 months now with this Spool.exe problem. In the event viewer I can see the "Faulting application spoolsv.exe..." message. I gathered from some research that this is related to corrupt printer driver. I tried twice to uninstall/reinstall printer drivers, but never succeeded. Every time after uninstall I made sure that I reinstalled the latest driver from Manufacturer web site.
Every time the spool service stops, there are some files (.SHD, .SPL) sitting in the C:\WINDOWS\system32\spool\PRINTERS folder, I have to manually remove all of them and restart the spool service. This used to happen at a rate of about once per week, now it happens more frequently. Maybe it is coincident, but I do notice as people print more labels to the Zebra printers, the problem occur more frequently. I could only suspect that it may have something to do with the Zebra driver.
Please advises are welcome, thank you in advance.
P.S. I have tried delete the printers from Registry, but I plan to use cleanspl.exe next time to tried to see if somehow I can revert back to the previous point before any printers were installed.